Although thermosetting resins comprising an unsaturated polyester and an addition-polymerizable resin as a skeleton are sometimes used alone, they are exclusively used as a composite material and about 80% of them produced are used as a fiber reinforced plastic (FRP). These thermosetting resins are applied to molding materials, laminates, adhesives, paints, etc. because formulation of fillers and additives (e.g. inorganic materials, etc.) and reinforcement by fibers are easily performed.
On the other hand, a three-dimensional structure is imparted to these resins by a curing reaction to convert into an insoluble/non-fusible solid. Therefore, it has hitherto been considered that these thermosetting resins are not easily decomposed and are not suitable for regeneration treatment and reuse, which results in disposal of them.
Molding materials are molding compounds prepared by filling inorganic materials (e.g. glass fiber, calcium carbonate, talc, silica, etc.) or organic materials (e.g. pulp, wood, etc.) into a resin as a binder. These molding materials are used for various applications in the industrial and household fields because large specific strength and specific rigidity are obtained by filling them.
Since these molding materials are composite materials, it is generally difficult to perform regeneration treatment after use. Furthermore, if the binder resin is a thermosetting resin, a three-dimensional structure is imparted to the binder resin by a curing reaction to convert into an insoluble/non-fusible solid. Therefore, it has hitherto been considered that the binder resin is not easily decomposed and is not suitable for regeneration treatment and reuse, which results in disposal of it. As the problem about wastes has attracted special interest recently, the development of the reuse/regeneration technique has been required and a study of conversion into raw materials by heat decomposition has started. However, advantages of the thermosetting resin or molding material (e.g. hardness, magnification of strength, heat resistance, non flammability, chemical resistance, etc.) make it difficult to perform waste disposal from the technical point of view.
Recently, an apparatus using a molding material comprising a thermosetting resin as a binder, e.g. molded motor, has been applied to household apparatuses, industrial apparatuses, business apparatuses and the like. Since the molded motor is superior in silent running properties, vibration-damping properties, insulating properties and maintainability and is capable of easily performing automated production because of compact size, its demand has been rapidly increased.
A molded stator of a molded motor, which has hitherto been used as A.C. motor, brushless D.C. motor and the like, generally has a construction, for example, disclosed in Japanese Laid-Open Patent Publication No. 1-214740. The molding material used herein contains a thermoplastic resin (e.g. polyethylene terephthalate, polyethylene, polypropylene, nylon, etc.) or a thermosetting resin (e.g. unsaturated polyester, vinyl ester resin, phenol resin, etc.) as a binder and further contains an additive (e.g. calcium carbonate, talc, carbon black, etc.).
The issue on wastes has become more serious and the urgent development of a volume-reduction technique and a disposal technique for reuse of discarded thermosetting compositions or molded articles of molding materials is required. Particularly, a large amount of fiber-reinforced unsaturated polyester resins are used for the production of fishing boats, tanks or large products such as housing materials and, therefore, problems about decomposition and regeneration treatment of wastes are serious. The molding materials comprising a thermosetting resin as a binder are exclusively used as a structural material because of magnification of strength and sometimes contain other materials such as metal. The metal is a valuable material which is expensive in comparison with a resin material and its possibility of inhibiting regeneration and reuse is a serious problem. That is, according to a conventional construction and disposal method, the problem about wastes remains unsolved with respect to the molded article of molding material at present.
At disposal of the molded motor, it is preferred to remove the molding material, thereby recycling metals (e.g. iron core, winding, etc.) as valuables. In conventional waste disposal, valuable materials are recycled by firstly shredding a molding material using a shredder and then selecting the valuable materials (e.g. iron core, winding, etc.) from shreds. Regarding the molded motor having the above-described construction, a shredding process is avoided because teeth of the shredder are easily damaged by the iron core and winding. Therefore, the molded motor is discarded without recycling the valuable materials, and buried under the ground, together with other wastes. Since the above-described molding material is not naturally decomposed by burying under the ground, silicon steel plates, copper wires, etc. used for the iron core and winding are buried without recycling in spite of high material value even after used as a motor. Furthermore, a conventional decomposition method such as volume reduction by heat decomposition can not be applied to the thermosetting resin used as the molding material. Accordingly, a conventional molded motor has a problem that shredding and decomposition of the molding material can not be applied and it is difficult to reuse valuable materials (e.g. iron core, winding, etc.) at disposal.
Accordingly, the primary object of the present invention is to provide a molding material capable of easily performing waste disposal.
Another object of the present invention is to provide a molded motor which can be separated and divided.